1 // SPDX-License-Identifier: GPL-2.0
2 /*
3 * gmidi.c -- USB MIDI Gadget Driver
4 *
5 * Copyright (C) 2006 Thumtronics Pty Ltd.
6 * Developed for Thumtronics by Grey Innovation
7 * Ben Williamson <ben.williamson@greyinnovation.com>
8 *
9 * This code is based in part on:
10 *
11 * Gadget Zero driver, Copyright (C) 2003-2004 David Brownell.
12 * USB Audio driver, Copyright (C) 2002 by Takashi Iwai.
13 * USB MIDI driver, Copyright (C) 2002-2005 Clemens Ladisch.
14 *
15 * Refer to the USB Device Class Definition for MIDI Devices:
16 * http://www.usb.org/developers/devclass_docs/midi10.pdf
17 */
18
19 /* #define VERBOSE_DEBUG */
20
21 #include <linux/kernel.h>
22 #include <linux/module.h>
23
24 #include <sound/initval.h>
25
26 #include <linux/usb/composite.h>
27 #include <linux/usb/gadget.h>
28
29 #include "u_midi.h"
30
31 /*-------------------------------------------------------------------------*/
32
33 MODULE_AUTHOR("Ben Williamson");
34 MODULE_LICENSE("GPL v2");
35
36 static const char longname[] = "MIDI Gadget";
37
38 USB_GADGET_COMPOSITE_OPTIONS();
39
40 static int index = SNDRV_DEFAULT_IDX1;
41 module_param(index, int, S_IRUGO);
42 MODULE_PARM_DESC(index, "Index value for the USB MIDI Gadget adapter.");
43
44 static char *id = SNDRV_DEFAULT_STR1;
45 module_param(id, charp, S_IRUGO);
46 MODULE_PARM_DESC(id, "ID string for the USB MIDI Gadget adapter.");
47
48 static unsigned int buflen = 512;
49 module_param(buflen, uint, S_IRUGO);
50 MODULE_PARM_DESC(buflen, "MIDI buffer length");
51
52 static unsigned int qlen = 32;
53 module_param(qlen, uint, S_IRUGO);
54 MODULE_PARM_DESC(qlen, "USB read and write request queue length");
55
56 static unsigned int in_ports = 1;
57 module_param(in_ports, uint, S_IRUGO);
58 MODULE_PARM_DESC(in_ports, "Number of MIDI input ports");
59
60 static unsigned int out_ports = 1;
61 module_param(out_ports, uint, S_IRUGO);
62 MODULE_PARM_DESC(out_ports, "Number of MIDI output ports");
63
64 /* Thanks to Grey Innovation for donating this product ID.
65 *
66 * DO NOT REUSE THESE IDs with a protocol-incompatible driver!! Ever!!
67 * Instead: allocate your own, using normal USB-IF procedures.
68 */
69 #define DRIVER_VENDOR_NUM 0x17b3 /* Grey Innovation */
70 #define DRIVER_PRODUCT_NUM 0x0004 /* Linux-USB "MIDI Gadget" */
71
72 /* string IDs are assigned dynamically */
73
74 #define STRING_DESCRIPTION_IDX USB_GADGET_FIRST_AVAIL_IDX
75
76 static struct usb_device_descriptor device_desc = {
77 .bLength = USB_DT_DEVICE_SIZE,
78 .bDescriptorType = USB_DT_DEVICE,
79 /* .bcdUSB = DYNAMIC */
80 .bDeviceClass = USB_CLASS_PER_INTERFACE,
81 .idVendor = cpu_to_le16(DRIVER_VENDOR_NUM),
82 .idProduct = cpu_to_le16(DRIVER_PRODUCT_NUM),
83 /* .iManufacturer = DYNAMIC */
84 /* .iProduct = DYNAMIC */
85 .bNumConfigurations = 1,
86 };
87
88 static struct usb_string strings_dev[] = {
89 [USB_GADGET_MANUFACTURER_IDX].s = "Grey Innovation",
90 [USB_GADGET_PRODUCT_IDX].s = "MIDI Gadget",
91 [USB_GADGET_SERIAL_IDX].s = "",
92 [STRING_DESCRIPTION_IDX].s = "MIDI",
93 { } /* end of list */
94 };
95
96 static struct usb_gadget_strings stringtab_dev = {
97 .language = 0x0409, /* en-us */
98 .strings = strings_dev,
99 };
100
101 static struct usb_gadget_strings *dev_strings[] = {
102 &stringtab_dev,
103 NULL,
104 };
105
106 static struct usb_function_instance *fi_midi;
107 static struct usb_function *f_midi;
108
midi_unbind(struct usb_composite_dev * dev)109 static int midi_unbind(struct usb_composite_dev *dev)
110 {
111 usb_put_function(f_midi);
112 usb_put_function_instance(fi_midi);
113 return 0;
114 }
115
116 static struct usb_configuration midi_config = {
117 .label = "MIDI Gadget",
118 .bConfigurationValue = 1,
119 /* .iConfiguration = DYNAMIC */
120 .bmAttributes = USB_CONFIG_ATT_ONE,
121 .MaxPower = CONFIG_USB_GADGET_VBUS_DRAW,
122 };
123
midi_bind_config(struct usb_configuration * c)124 static int midi_bind_config(struct usb_configuration *c)
125 {
126 int status;
127
128 f_midi = usb_get_function(fi_midi);
129 if (IS_ERR(f_midi))
130 return PTR_ERR(f_midi);
131
132 status = usb_add_function(c, f_midi);
133 if (status < 0) {
134 usb_put_function(f_midi);
135 return status;
136 }
137
138 return 0;
139 }
140
midi_bind(struct usb_composite_dev * cdev)141 static int midi_bind(struct usb_composite_dev *cdev)
142 {
143 struct f_midi_opts *midi_opts;
144 int status;
145
146 fi_midi = usb_get_function_instance("midi");
147 if (IS_ERR(fi_midi))
148 return PTR_ERR(fi_midi);
149
150 midi_opts = container_of(fi_midi, struct f_midi_opts, func_inst);
151 midi_opts->index = index;
152 midi_opts->id = id;
153 midi_opts->in_ports = in_ports;
154 midi_opts->out_ports = out_ports;
155 midi_opts->buflen = buflen;
156 midi_opts->qlen = qlen;
157
158 status = usb_string_ids_tab(cdev, strings_dev);
159 if (status < 0)
160 goto put;
161 device_desc.iManufacturer = strings_dev[USB_GADGET_MANUFACTURER_IDX].id;
162 device_desc.iProduct = strings_dev[USB_GADGET_PRODUCT_IDX].id;
163 midi_config.iConfiguration = strings_dev[STRING_DESCRIPTION_IDX].id;
164
165 status = usb_add_config(cdev, &midi_config, midi_bind_config);
166 if (status < 0)
167 goto put;
168 usb_composite_overwrite_options(cdev, &coverwrite);
169 pr_info("%s\n", longname);
170 return 0;
171 put:
172 usb_put_function_instance(fi_midi);
173 return status;
174 }
175
176 static struct usb_composite_driver midi_driver = {
177 .name = longname,
178 .dev = &device_desc,
179 .strings = dev_strings,
180 .max_speed = USB_SPEED_HIGH,
181 .bind = midi_bind,
182 .unbind = midi_unbind,
183 };
184
185 module_usb_composite_driver(midi_driver);
186